Pneumatic sanding pad



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H. HUMPHREYS PNEUMATIC SANDING PAD Filed Feb. 28 1921 2 Sheets-Sheet 1 INVENTOQ HUGH H11 murga/5.

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H. HUMPHREYS PNEUMATI C SANDING PAD Filed Feb. 28. 192] 2 Sheets-Sheet 2 NNE 'Z4 11M/Emol HU GH Humpml A ORN iw Patented ay i3, i924. A

" wam FCE HUGH H'UMPHREYS, OF GRAND RAPIDS, MICHIGAN, ASSIGNOR TO OLIVER IMAGHIN"v ERY COMPANY, OF GRAND RAPIDS, MICHIGAN, A CORPORATION F MICHIGAN.

PNEUMATIC SANDING PAD.

Application filed February 28, l1921. Serial No. 448,741.

sanding padbwhich maybe used either man? uallyv or lin connection with a belt sanding machine," so constructed that it is possible to lcompletely `finish work by sanding and thus smoothing the same irrespective of certain irregularities in theA surfaces sanded,'

the pad acting to force the sanding material against all parts of the surface and into various depressions which may be present in thesurface of the work' acted upon. VMore specifically, my invention relates to -a pneumatic" sanding pad capable-of yielding and conforming instantly to more or less slight 'irregularities in the surface` worked whereby every portion of a piece of material surface operated against 1n connection with the -pad is sanded "and smoothed, leaving no rough portions, orv

V parts partially smoothed.

. It is a -primary ob]ect and purpose of the noted., in a simple and economical manner and ada ted to be attached to sanding machines ci) the belt sander type, or available for use by hand, all of which will appear .fully as understanding of `the invention is had'fromthe following description, taken in'conne'ction with the accompanying drawings, in which, x' Fig. 1 is'an elevationshowing my invention applied to a belt sanding machine. l

Fig. 2 is a section on the plane of line 2 2, of Fignland looking inthe direction of the pad and associated parts.v Fig. 3 is anpen-larged longitudinal section through the pad. Fig. 4 is a plan lvie,w thereof. v

Fig. 5 is a perspective view of the pad modified for hand operation, and

Fig. 6 Ais a fragmentary enlargedi section of the pad shown in 5, at one end thereof. A

Like reference characters refer to like parts in the dierent figures of the drawings.

In the construction of the pad, a plate 1 of sheetv metal with an upturned flange 2 60 entirely around it is provided to which a fabric casing is attached, between which and the plate a rubber inner tube or bag. 4 is first placed. The'outer casing 3 is connectedto the flange 2 bya laclng 5 passing e5 through openings in vthe flange andthe upper portions of the casing. IAn air valve 6 is attached to the bag 4 and extends through an opening in plate 2, it being obvious that the bag may be inflated through said valve 70' to any desired degree of pressure.

When used with a belt sanding machine, a block 7 is connected centrally of and to the upper side of the plate 1 having a socket for the reception of a ball-like head 8 which 75 is retained in the socket by retaining mem-v bers 9 fastened byscrews or equivalent fas'- tening means to the block 7 The head 8 Y is made at the lower end of a vertical rod 10 and with thisconnection itis apparent 80\ that the pad may have universal 'an ular mrvement with respect tothe axis o the ro The sanding machinewith which this pad is adapted to be used includes a horizontal g5 track or trolley bar 11 on which a carriage invention, to makena pad of the character -12 is movably mounted so as to traverse the 35 length thereof, trolley rollers or wheels 13 on the` carriage engaging the track. A bracket 14 projects rearwardly from` the 90 carriage to which the rear endl of a lever 15 is pivotally connected'at 16, the lever ex;l tending a distance in front of the carriage and being equipped with an operating handle 15 at its front end. The lever has op- 95 erative connection to the rod 10 at a point between its ends so that on turning the lever about its ivot at 16, the rod and attached pad may e moved vertically. The `rod 10 is slidably mounted in suitable guides 17 100 on the carriage and at its upper end passes through a leaf spring 18, receiving nuts -19 I at its upper end for connection with the s ring. The tendency of the 'spring isto f e evate the rod and pad to an upper' inop-nol erative position.

In a belt sanding machine, an endless belt 2O passes at its lower run under the pad, being carried around pulleys or wheels 21 which may be driven in any suitable Inanner. The Work to be sanded is located under the lower run of the belt, as indicated at 22, and the pad brought against the upper side of the belt by depressing the lever l5. The outer sides of the belt are Iabrasive and held against the upper side of the work, serve to smooth and-finish the same. The bag 4 is readily yieldable and the outer casing of canvas or like fabric is likewise yieldL able, While the belt conforms to irregularities on 'the surface of the Work, being pressed into operating contact with all parts of the surface thereof due to the complete flexible and yielding nature of the pad which presses the abrasive belt against the work. This insures that the surface sanded shall be finished at every part Without leaving any rough or partially finished areas.

In Figs. 5 and 6, the pad hasa handle23 attached to the plate l and projecting therefrom shaped for engagementv by the hand.

Sand paper 24, or the like is placed against .the outside of casing 3 and bent at its ends over flange, 2, being secured detachably by clips or in any other suitable manner.

Likewise, a protective canvas cover 26 may be placed over the pad when used on the emachine and secured by clips 25, being replaced whenever necessary. The construction of hand operated pad is also capable prising a plate of metal having an upturned l flange around it at its edges, said flange having a plurality of spaced apart openings therein, a flexible fabric casing having an open upper endinto which the plate is inserted, said casing adjacent its upper edges also having a plurality of spaced apart:

openings therethrough, lacings passing through the openings in the flange and casing for connecting the same together, and

an infiatableand expansible air tight bagrlocated within the ycasing and under ther.

plate, substantially as and for the purposes described. v

2.' A ad of the class described, comprising a re atively rigid plate,'a fabric vcasing member open at its upperl side, meansffor connecting 'the casing member at theplate to` form a containing casing'of which the plate is the upper side, a rubber bag within said casing, and means to inflate said bag, substantially as described. i

In testimony whereof I affix my signature.

. HUGrf HUMPHREYS. 

